Going for the sidekicks here...
Snow White: that would be Sneezy. It'd be fun to watch him blow everything around.
Pinocchio: that's Figaro - he's a cute and sometimes mischievous cat. ^^
Fantasia: the little unicorns during the Pastoral scene - fun and a bit frolicsome. ^_~
Dumbo: the Pink Elephants. For a simply
mad time, look no further!
Bambi: Flower. Very laid-back and also friendly. Not to mention stinky!
Cinderella: Gus (Augustus). Very animated and energetic. Cute voice too.
Alice: would be the Cheshire Cat - for obvious reasons!
Peter Pan: Tinkerbell, who else? She's just darling, and the red cheeks....LOL!
Lady and the Tramp: the Siamese Cats, as they're very sneaky and lots of fun.
Sleeping Beauty: I'd go for Merryweather also, as she should have let the dress be blue!
101 Dalmatians: Sgt, Tibbs, for he's quite slapstick with his crazy antics.
The Sword in the Stone: ooh, Madame Mim for sure! What a blast we'd have to go and be crafty and sly! ^__^
The Jungle Book: Louie, naturally. He's got the vibe, the jive and is a swinging character! ^^;
The Aristocats: it'd have to be Scat Cat - do you notice a trend in these? They're mostly swinging types!
Robin Hood: Lady Kluck, for her cheery disposition, and she'd be a great gal to have in a fight!
The Rescuers: Evinrude. He's not much of a talker, but he's a good friend in a tight pinch.
The Black Cauldron: I think I would enjoy my time with Creeper - he's just a slacker with very fun actions when in trouble.
The Little Mermaid: Max, for being so slobbery, and add
The Princess and the Frog's Stella to that. Why her and not Ray or Louis? Well, just because!
Tangled: that's Pascal, for sure. He's lovable and got a great sense of protection over his friends, and because he can change colour! ^^
Whew, a long list! I was going to go for all animations, but realised how long that'd make this, so I stopped! O_o